One of my most extensive jobs so far was to draw around 400 pictures for a Swiss driving school app called Simpli. The task was to take all the official pictures that the authorities use for the theoretical test and give them a homogenous modern look. The originals were a mix of computer renderings of various quality and photographies from the 1960s all the way to the 21st century. It took some time but I think it was worth it and the app has been well-received by the public.
Here are some examples: